TY - JOUR TI - Light-Activated Reversible Imine Isomerization: Towards a Photochromic Protein Switch AU - Berbasova, Tetyana AU - Santos, Elizabeth M AU - Nosrati, Meisam AU - Vasileiou, Chrysoula AU - Geiger, James H AU - Borhan, Babak T2 - Chembiochem : a European journal of chemical biology AB - Mutants of cellular retinoic acid-binding protein II (CRABPII), engineered to bind all-trans-retinal as an iminium species, demonstrate photochromism upon irradiation with light at different wavelengths. UV light irradiation populates the cis-imine geometry, which has a high pKa , leading to protonation of the imine and subsequent "turn-on" of color. Yellow light irradiation yields the trans-imine isomer, which has a depressed pKa , leading to loss of color because the imine is not protonated. The protein-bound retinylidene chromophore undergoes photoinduced reversible interconversion between the colored and uncolored species, with excellent fatigue resistance. DA - 2016/03/02/ PY - 2016 DO - 10.1002/cbic.201500613 VL - 17 IS - 5 SP - 407 EP - 414 J2 - Chembiochem LA - eng SN - 1439-7633 UR - https://pubmed.ncbi.nlm.nih.gov/26684483 AN - 26684483 DB - PubMed KW - *Ultraviolet Rays KW - Chromatography, High Pressure Liquid KW - Imines/*chemistry KW - Isomerism KW - Proteins/*chemistry KW - Retinaldehyde/chemistry KW - Spectrophotometry, Ultraviolet KW - imines KW - isomerization KW - photochemistry KW - protein engineering KW - retinal ER -